147514-19-0Relevant articles and documents
Diastereoselective noncovalent synthesis of hydrogen-bonded double-rosette assemblies
Prins, Leonard J.,Hulst, Ron,Timmerman, Peter,Reinhoudt, David N.
, p. 2288 - 2301 (2007/10/03)
Chiral centers present either in the dimelamine components of calix[4]arene 1 or in the cyanurate components CA quantitatively induce one handedness (P or M) in the corresponding hydrogen-bonded assemblies 13·(CA)6 (de>98%). The high degree of chiral induction results from the presence of six chiral centers in close proximity (Cα) to the core of the assembly. A much lower level of chiral induction is observed for assemblies with chiral centers that are more remote (Cβ). All diastereomerically pure assemblies 13·(CA)6 exhibit very high CD activities (|Δεmax|~100 L mol-1cm-1), in sharp contrast to the low CD activities (|Δεmax|≤8 L mol-1cm-1) shown by the free components. The assemblies display spontaneous resolution under thermo-dynamically controlled conditions (i.e., heteromeric assemblies containing both peripheral R and S centers are not observed. Remarkable assembly behavior is observed if both components 1 and CA are chiral. In general, formation of well-defined assemblies is only observed when both components contain unidirectional information for the induction of either M or P chirality.
A Short Stereocontrolled Synthesis of Hydroxyethylene Dipeptide Isosteres
Jones, D. Michael,Nilsson, Bo,Szelke, Michael
, p. 2286 - 2290 (2007/10/02)
A stereocontrolled synthesis of protected hydroxyethylene dipeptide isosteres 14 and 16 is described.It provides the 2R,4S,5S epimers required for the preparation of aspartic proteinase inhibitors.The choice of a benzene ring as a precursor to the carboxy